Generally, the conventional diagnostic X-ray device takes an x-ray picture of an internal body for a patient on an X-ray sensitive film. The film needs some time to be printed for confirming the patient state. However, recent development in the semi-conductor technology makes the patient state recognized by the diagnostic X-ray device in real time without delay via a digital X-ray detector utilizing a thin film transistor (hereinafter, referred to as TFT) as a switching element. The digital x-ray detector has been researched until today.
Hereinafter, the structure and function of the digital X-ray detector is described as follows.
FIG. 1 is a schematic view illustrating the conventional digital X-ray detector.
Referring to FIG. 1, the conventional digital X-ray detector includes a substrate 1, a plurality of TFTs 3, a plurality of storage capacitors 10, and a plurality of pixel electrodes 12 disposed on the substrate 1, a light conductive layer 2 on the pixel electrodes 12, a protective layer 20, a conductive electrode 24, and a direct power source 26 of high voltage.
The light-conductive layer 2 generates an internal electric signal such as the stream of pairs of electron and hole 6 in proportion to an intensity of the external signal such as the electromagnetic wave incident thereon. Further, the light a conductive layer 2 also transforms an outer signal, for example, an X-ray, into an electrical signal.
The electron in the pair of electron and hole 6 is accumulated on the pixel electrode 12 disposed below the light conductive layer 2 by a predetermined voltage E of the conductive electrode 24 applied from the direct power source 26, and is stored in the storage capacitor 10 formed with a common electrode that is connected to the ground. The TFTs 3 move the electrons stored in the storage capacitor 10 to an image-processing device in an outside of the detector 100 to thereby form an X-ray image.